1. Field of the Invention
The present techniques relate generally to fracturing and propping subterranean operations. In particular, the present techniques relate to proppants comprising PPS for use in subterranean formations.
2. Description of the Related Art
This section is intended to introduce the reader to various aspects of art which may be related to various aspects of the present invention that are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Fracturing (e.g. hydraulic fracturing) is a common stimulation technique used to enhance production of fluids from subterranean formations. In a typical hydraulic fracturing treatment, a fracturing fluid containing a solid proppant is injected into the wellbore at pressures sufficient to create or enlarge a fracture in the subterranean formation. The proppant is deposited in the fracture, where it remains to prop the fracture. This allows fluids which were previously unavailable for recovery (or difficult to recover) to migrate from the formation to the wellbore through the fracture. Because well productivity depends on the ability of a fracture to conduct fluids from the formation to the wellbore, fracture conductivity is an important parameter in determining the degree of success of a hydraulic fracturing treatment.
Subterranean wells (such as hydrocarbon producing wells, gas producing wells, water producing wells, and injection wells) may be stimulated by fracturing treatments. In hydraulic fracturing treatments, a fracturing fluid (e.g., a viscous fluid), which may also function as a carrier fluid, is pumped into a portion of a subterranean formation at a rate and pressure such that the subterranean formation breaks and one or more fractures are formed. Typically, particulate solids (e.g. graded sand) are suspended (or slurried) within the fracturing fluid and deposited in the fractures of the subterranean formation. These particulate solids or “proppant” (or “proppants”) may serve to reduce the possibility of the subterranean formation fractures fully closing. By keeping the fracture from fully closing, the proppants (i.e., particulates) allow the formation of conductive paths for materials (e.g., water, oil, gas, hydrocarbons, waste, etc.) to flow in the subterranean formation.
Some commonly used proppants include graded sand, bauxite, ceramics, or even nut hulls. Typically, the proppant particles are placed in the fracture in a concentration such that they formed a relatively tight pack of particles. Unfortunately, the pressure utilized to form the fractures is released the fractures close upon the proppant and the proppant may become crushed or compacted. The crushing or compacting of the proppants can potentially form non-permeable or low permeability masses within the fracture and may result in decreased flow of desirable materials (e.g. oil, water, and/or gas) from the subterranean formation.
Unfortunately, material flow through the subterranean formation may be reduced by small proppants or fines resulting from the crushing of the proppants failure of the formation rock, or both, as stress builds when the fracturing pressure is released. Such stresses may cause the proppant to be compressed together such that fines are generated from the proppant particles and/or reservoir matrix. Additionally, fines composed of formation material (e.g., shale, sand, coal fines, etc.) may present similar problems. The formation fines may be produced within the fractured subterranean formation due to the stresses and forces applied to the formation during fracturing or from the release of the fracturing pressure.
In sum, the degree of success of a fracturing operation depends, at least in part, upon the strength of the proppant within the subterranean formation when the fracturing pressure is released. If the proppants are broken, the pieces of broken proppant (e.g. fines) may plug the interstitial spaces of the fractured subterranean formation and reduced the flow of material from the subterranean formation. What is needed are proppants which have the strength to resist crushing when the fracturing pressure is released from the subterranean formation.